This invention generally relates to surgical ablation probes and the use of such probes in the treatment of cardiac arrhythmia and particularly atrial fibrillation and atrial flutter.
Atrial fibrillation is the disorganized depolarization of a patient's atrium with little or no effective atrial contraction. Prior methods for treating a patient's arrhythmia include the use of anti-arrhythmic drugs such as sodium and calcium channel blockers or drugs which reduce the Beta-adrenergic activity. Other methods include surgically sectioning the origin of the signals causing the arrhythmia or the conducting pathway for such signals. However, the surgical technique is quite traumatic and is not suitable for a large number of patients. A more frequently used technique to terminate the arrhythmia involves ablating the heart tissue which causes the arrhythmia by a laser beam or high frequency electrical energy such as RF or microwave energy, to a desired arrhythmogenic site or pathway on the patient's endocardium. In the latter method, intravascular electrophysiological (EP) devices can be used to form lesions within a patient's atrial chamber to provide results similar to the surgical segregation techniques in terminating atrial fibrillation, but with significantly reduced trauma.
Typically, the ablation device is advanced within a patient's vasculature and into a heart chamber, and a lesion is formed on the endocardium when RF electrical energy is emitted from electrodes on the device. Typically, RF ablation techniques produce lesions of a small area, so that several lesions are typically formed to completely ablate an area. While these procedures of forming lesions from inside the heart chamber have met with some degree of success, there remains a need for suitable devices for forming such lesions in the patient's heart wall from the exterior thereof, particularly during a minimally invasive procedure while the heart is beating.